Well packer

ABSTRACT

An improved well packer having upper and lower slips and expanders for permanent anchoring, is further provided with separate upper and lower mandrel sections. After the packer is permanently anchored in a well casing or tubing, the packer may be retrieved by pulling the upper mandrel section to disconnect a segmented nut assembly which couples the upper expander to the lower mandrel section, and which also keeps the upper expander wedged between the upper slips and the upper mandrel section. When the nut is released, the compression loading on the packing is relieved to enable its relaxation, and the setting pressure on the upper and lower slips is also achieved. Further upward travel of the upper mandrel section carries the upper slip out of engagement with the well casing, and thereafter draws the lower cone upward and out from between the lower slip and the lower mandrel section.

United States Patent [72] Inventor David E. Young 11ouston,Tex. [2]] AppLNo. 889,540 [22] Filed Dec.31,1969 45] Patented Jan. 4, 1972 [73] Assignee SchlumbergerTechnology Corporation New York, N.Y.

[54] WELL PACKER 13 Claims, 5 Drawing Figs.

[52] U.S.Cl 166/134, 166/123 [51] 1nt.Cl ..E2lb23/06. E2lb 33/129 [50] FieldoiSearch 166/134, 135,123,120

[56] References Cited UNITED STATES PATENTS 3,142,338 7/1964 Brown..... 166/120 3,244,233 4/1966 Villalon... 166/134X 3,374,837 3/1968 Pageetal. l66/135X 3,398,795 8/1968 Elliston ABSTRACT: An improved well packer having upper and lower slips and expanders for permanent anchoring, is further provided with separate upper and lower mandrel sections. After the packer is permanently anchored in a well casing or tubing, the packer may be retrieved by pulling the upper mandrel section to disconnect a segmented nut assembly which couples the upper expander to the lower mandrel section, and which also keeps the upper expander wedged between the upper slips and the upper mandrel section. When the nut is released, the compression loading on the packing is relieved to enable its relaxation, and the setting pressure on the upper and lower slips is also achieved. Further upward travel of the upper mandrel section carries the upper slip out of engagement with the well casing, and thereafter draws the lower cone upward and out from between the lower slip and the lower mandrel section.

PATENIEUJAI 4W2 'SHEET 1 nr 2 David E. Young INVENTOR a w @W/ F/GI ATTORNEYS David E. Young INVE N TOR A TTORNE VS WELL PACKER BACKGROUND OF INVENTION This invention relates to well packers and the like, and more particularly relates to permanently anchored packers which are adapted to be retrieved without damage to either the well or the packer.

There are many instances, such as production operations, where it is desirable to define and segregate one portion of a borehole from another. In those instances wherein the borehole is lined with a steel casing or the like, this is achieved by setting a packer assembly in the casing at such depth as may be desired.

In some instances, it may be desired that the well be packed off only temporarily, wherein in many other instances it is intended that the packer be permanently set in the well. So-called temporary packers are usually designed to be wedged in the casing in such manner as to resist movement in only one direction. This is because retrieval of a temporary packer is usually achieved by shifting in the opposite direction to disengage it from the interior of the casing. On the other hand, permanent packers are wedged in the casing in a manner opposing movement in either direction. Hence, most permanently anchored packers cannot be dislodged without damage to either the casing or the packer.

It is a common occurrence for it to become desirable to remove a packer that has been permanently installed. Since this usually requires a drilling operation and consequent destruction of the packer, this may be quite costly. Moreover, it has become common practice to construct permanent packers of drillable materials so that they can be easily shattered by the drill bit. Although this provides a substantial saving insofar as drilling time is concerned, it has the disadvantage that a frangible packer may be an inherently weaker packer. Furthermore, the fragments and other debris from the shattered packer tend to clutter the bottom of the borehole, and may interfere with subsequent operations. In addition, a permanent packer is an expensive piece of equipment as such.

There have been many attempts to provide a packer which is adapted to be anchored immovably in the borehole, but which is also adapted to be retrieved whenever desired without damage to either the packer or the interior of the borehole or casing. However, none of these retrieval permanent packers have met with complete acceptance by the oil and gas industry.

In many cases, the packers have been both anchorable and retrievable, but either special setting techniques or equipment have been required to install the packer, or else special retrieval techniques and equipment have been necessary. In these cases, it has often cost more to retrieve such a packer than it would have cost to drill through and destroy it. Other packers such as that depicted in US. Pat. No. 3,398,795, have been capable of being installed and retrieved by special setting and removal equipment, however, such equipment and the packer itself are quite expensive.

These and other disadvantages of the prior art are completely overcome with the present invention, and novel packer means is provided herein which is adapted to be anchored immovably in a well casing or the like by conventional setting techniques, and which is also adapted to be selectively retrieved by conventional retrieval techniques and equipment without damage to either the packer assembly or the casing.

THE INVENTION In a preferred embodiment of the invention, a packer assembly is provided which has a conventional elastic packing body located intermediately of upper and lower slips and expanders. Thus, the packer may be anchored permanently in a well casing or the like by setting the upper slips in a conventional manner to oppose upward movement of the packer, and by setting the lower slips in a conventional manner to oppose downward movement of the packer in the casing.

The packer assembly is provided, however, with a mandrel assembly having separate upper and lower mandrel sections which may be moved to and from each other to a limited extent. The mandrel sections are initially held together by one or more shearpins or the like, whereby the packer may be set in the casing in a conventional manner. If the packer is to be retrieved, however, the upper mandrel section is preferably drawn upward from the lower mandrel section until means, such as a segmented nut, becomes disengaged in a manner to thereby release the compression loading in the packing and setting force on the upper expander and slips. Further upward movement of the upper mandrel section will then carry the upper slips completely free of the upper expander.

As hereinbefore stated, the upper mandrel section can be raised independently of the lower mandrel section only a limited distance. Thus, further upward movement of the upper mandrel section will engage and carry the lower mandrel section with it upward through the borehole. Since the lower slips and expander are slidably mounted on the lower mandrel section, the lower mandrel section will travel upward independently of the lower slips and expander a limited distance. After this limited distance has been transversed, however, the lower mandrel section preferably engages the lower expander to carry it upward away from the lower slips until the lower slips are disengaged from the casing. Thereafter, further upward movement of the upper mandrel section will raise the entire packing assembly through the casing without damage to or loss of any portion of the packing assembly (except for shearpins and the like which are severed when the packing assembly is initially set) and without damage to the casing.

Accordingly, it is an object of the present invention to provide an improved packing assembly which is adapted to be immovably anchored in a casing or the like, and which is also retrievable without damage to or loss of any portion of the assembly and without damage to the casing.

It is further an object of the present invention to provide an improved packing assembly which is adapted to be immovably or permanently anchored in a casing by conventional setting techniques, and which is also adapted to be retrieved by conventional retrieval techniques and equipment without damage to or loss of any portion of the packing assembly and without damage to the casing.

These and other objects and features of the present invention will become apparent from the following detailed description, wherein reference is made to the figures in the accompanying drawings.

IN THE DRAWINGS FIG. l is a pictorial representation, partly in cross section, of a packing assembly embodying one form of the present invention, wherein the packing assembly is depicted in a relaxed condition prior to being anchored in a casing.

FIG. 2 is a pictorial representation, also partly in cross section, of the apparatus depicted in FIG. 1, wherein the packing assembly is depicted in a set condition after being anchored in the casing.

FIG. 3A is a pictorial representation, also partly in cross section, of the upper portion of the apparatus depicted in FIGS. 1 and 2, wherein the packing assembly is depicted with the upper slips and cones disengaged by and during retrieval of the packing assembly.

FIG. 3B is a pictorial representation, also partly in cross sec tion, of the lower portion of the apparatus depicted in FIGS. 1 and 2, wherein the packing assembly is depicted with the lower slips and cones disengaged by and during retrieval of the packing assembly.

FIG. 4 is a cross-sectional representation of a portion of the apparatus illustrated in FIG. 1.

DETAILED DESCRIPTION Referring now to FIG. 1, there may be seen a pictorial representation, partly in cross section, of a packing assembly suitable for the purposes of the present invention, and more particularly including an upper mandrel section 3 having a slotted portion 4 and a cam shoulder portion 5. As may be further seen, the upper mandrel section 3 is preferably provided with inside ratchet teeth 6 for engaging the lower end of a conventional retrieval tool 42 (not depicted in FIG. 1) and is further provided with an upper slip carrier 7 slidably positioned about its exterior surface and adjacent its upper end. The upper slip carrier 7 is preferably fixedly attached to the upper mandrel section 3 by means of a conventional shearpin 8 or other suitable means.

As further illustrated in FIG. 1, a suitable slip of slips 12 are preferably slidably disposed about the upper mandrel section 3 and interconnected loosely with the lower end of the upper slip carrier 7 by means of a T-connection 11 or other conventional means. It may thus be seen that downward movement of the upper slip carrier 7 about the upper mandrel section 3 will urge the upper slips 12 downwardly upon and outwardly of an expander 13 which is also slidably positioned upon the upper mandrel section 3. It will be noted in FIG. 1, however, that the upper expander 13 is located adjacent the slotted portion 4 of the upper mandrel section 3, and is provided with an interior groove to accommodate and receive the cam shoulder portion of the upper mandrel section 3, for reasons which will hereinafter be explained in detail.

As may further be seen in FIG. 1, the upper slip carrier 7 is preferably provided with an interior longitudinal recess for receiving and accommodating one or more splines 9 on the exterior surface of the upper mandrel section 3. The purpose of these splines 9 and recesses 10 is to permit limited longitudinal movement of the upper slip carrier 7 relative to the upper mandrel section 3, but to prevent rotation or circumferential travel of the upper slip carrier 7 about the upper mandrel section 3.

As may be seen, the packing assembly illustrated in FIG. 1 further includes a lower mandrel section 20 having an enlarged or upset abutment portion 40 at its upper end, and having a resilient packing element 21 of conventional design mounted immediately below the lower shoulder of the abutment portion 40. As depicted in FIG. 1, antiextrusion springs 22 may be incorporated with the resilient member 21 for conventional reasons.

Referring again to the upper mandrel section 3, it may be seen that this member is provided with a longitudinal slot 19 at its lower end, and that the upper end of the lower mandrel section 20 is provided with a suitable pin 18 which is disposed in the slot 19. The upper end portion of the abutment portion 40, of the upper mandrel section 3, is also preferably provided with inside threads 15 for threadedly engaging the exterior surfaces of a segmented nut assembly 14 having smooth inside surfaces slidably abutting the exterior of the upper mandrel section 3. It will further be noted that when the segmented nut assembly 14 is fitted between the upper and lower mandrel sections 3 and 20, as indicated in FIG. 1, the nut assembly 14 provides a stop against slidable downward movement of the upper cone 13. In addition, it should be noted that the annular spacing 16 between the confronting surfaces of the upper and lower mandrel sections 3 and is greater immediately below the segmented nut 14, than it is between the surfaces of the upper and lower mandrel sections 3 and 20 which are contacted by the nut assembly 14. Further, it will be noted that the spacing or annular recess 16 is normally large enough to receive the components of the segmented nut assembly 14, as will hereinafter be explained in detail.

As indicated in FIG. 1, the upper and lower mandrel sections 3 and 20 are fixedly attached, one to the other, by means of a shear ring 17 or other suitable frangible connecting device, prior to being run into the casing 2 which surrounds the packing assembly. As further depicted in FIG. I, the upper and lower mandrel sections 3 and 20 are telescoped together until the pin 18 is in abutting relationship with the upper end of the slot 19. Accordingly, the upper mandrel section 3 may be pulled upward by suitable means (as will hereinafter be explained) and independently of the lower mandrel section 20, by shearing the shear ring 17, whereupon the upper mandrel section 3 may move upwardly until the lower surface of the slot abuts the lower surface of the pin 18. This will create a longitudinal enlargement of the annular recess 16, ans also release the segmented nut assembly 14. Further upward movement of the upper mandrel section 3 will then carry the lower mandrel section 29 with it due to the engagement provided by the pin 18.

Referring now to the lower mandrel section 20, there may be seen a lower expander 25 located immediately below the lower surface of the elastic packing element 21, and in a reversed configuration relative to the upper expander 13. The lower expander 25 differs, however, in that it is provided with one or more splines or keys 23 which are accommodated in a suitable longitudinal slot or slots 24 in the exterior surface of the lower mandrel section 20.

Lower slips 26 are slidably positioned below the canted surface of the lower expander 25, and are interconnected with a suitable lower slip carrier 29 by means of a suitable T-connection 30 or the like. As may be seen in FIG. 1, the lower slip carrier 29 is slidably mounted on the lower end of the lower mandrel section 20, and is preferably fixedly secured thereto by means of a snap ring 31 or other suitable fastening device.

Although the lower slips and expander 26 and 25 are slidably movable, one to the other, they are also preferably linked together by a loose dovetail connection 27. Similarly, the upper slips 12 and expander 13 are preferably linked together by a loose dovetail connection 28.

As hereinbefore stated, the packing assembly depicted in FIG. 1 is represented as having been positioned in a suitable well casing 2, preparatory to being anchored permanently in the casing 2. Accordingly, conventional setting equipment comprising a tension member 33 for pulling upward through the casing, and a compression member 34 (shown in phantom lines) for pushing down through the casing 2, may be utilized as illustrated. More particularly, it will be seen that the tension member 33 is provided with a shear ring 32 or other suitable means for engaging the lower end of the lower slip carrier 29, while the lower end of the compression member 34 is urged downwardly about the upper end of the upper mandrel section 3, and against the upper end of the upper slip carrier 7. The illustrated packing assembly may now be conveniently installed or set in the casing 2 by driving the compression member downwardly while pulling the tension member 33 upwardly in the casing 2 and in opposition to downward movement of the compression member 34.

Accordingly, when the tension member 33 is held in position, downward pressure of the compression member 34 will urge the upper slip carrier 7 slidably down the exterior of the upper mandrel section 3. The shcarpin 8 is first severed, and thereafter the upper slip carrier 7 urges the upper slips 12 downwardly over the canted surface of the upper expander 13, and outwardly into engagement with the interior surface of the casing. Upward movement of the tension member 33, at the same time, tends to pull the lower slip carrier 29 upward about the lower end of the lower mandrel section 20, thereby urging the lower slips 26 and expander 25 upwardly against the lower end of the packing element 21. In this respect, it should be noted that the snap ring 31 is preferably collapsible into a suitable annular groove about the lower end of the lower mandrel section 20. Further, it should be noted that the lower slip carrier 29 is preferably provided with an abutting annular shoulder 39 which tends to ride over and compress the snap ring 31 into its groove, until the shoulder 39 overrides and rises about the snap ring 31. Upward pressure of the lower expander 25 against the packing element 21, tends to squeeze it against the lower surface of the abutment portion 40 of the lower mandrel section 20, to thereby expand the resilient packing element 21 outwardly and into fluidtight engagement with the inside surface of the casing 2. During setting, the lower slips 26 are slid over the canted surface of the lower expander 25, to urge the lower slips 26 into gripping engagement with the inside surface of the casing 2.

When the lower slips 26 have been securely engaged with the inside surface of the casing 2, further upward movement of the tension member 33 causes the shear ring 32 at the end of the lower slip carrier 29 to be severed, and the tension member 33 may then be drawn out of the packing assembly, and out of the casing 2. At this point, the compression member 34, which is also a part of the entire setting tool assembly (not depicted) may also be removed from the interior of the casing 2. It may then be seen that the upper slips oppose upward travel of the packing assembly through the casing 2, and that the lower slips 26 oppose downward travel of the packing assembly, and that the packing assembly is accordingly permanently anchored in the interior of the casing Referring now to FIG. 2, there may be seen a pictorial illustration of the apparatus generally depicted in FIG. 1, except that the tension and compression members 33 and 34 have now been removed, and that the lower end portion of a suitable production stinger 35 has now been inserted into the upper and lower mandrel sections 3 and 20. As may further be seen, the production stinger is provided with a wide annular exterior groove or shoulder 37, positioned so as to prevent inward contraction or collapse of the slotted portion 4 of the upper mandrel section 3, when the production stinger 35 is fully inserted within the packing assembly. In this respect, it will be noted that the production stinger 35 is also provided with a suitable exterior shoulder 38 for being landed on an internal canted portion of the upper mandrel section 3, immediately below the ratchet threads or teeth 6, to stop downward travel of the production stinger 35 when it has been fully inserted within the illustrated packing assembly. In addition, annular seal rings 36, of suitable configuration are preferably disposed about the exterior surface of the production stinger 35 at its lower end. It will thus be noted that the position of the annular expansion shoulder 37 provides that the cam shoulder portion 5 of the slotted portion 4 of the upper mandrel section 3, is locked within the internal annular groove of the upper expander 13.

Referring now to FIGS. 3A and B, there may be seen pictorial illustrations of the upper and lower portions of the packing assembly depicted generally in FIGS. 1 and 2, but wherein the various components are depicted in relaxed condition for disengagement and withdrawal of the packing assembly from within the tubing 2. In particular, it will be noted that the production stinger 35 depicted in FIG. 2 has now been removed, and that a suitable inside grapple-type retrieval tool 42 has been inserted downwardly within the upper end of the upper mandrel section 3. More particularly, it may be seen that the exterior ratchet teeth 41 located at the lower end of the retrieval tool 42 has been thrust downwardly into the upper end of the upper mandrel section 3 to engage the ratchet teeth or threads 6 located therein.

The packing assembly depicted in the drawings may be retrieved simply by drawing the retrieval tool 42 upward through the casing 2 after it has engaged with the ratchet threads 6 of the upper mandrel section 3. As the upper mandrel section 3 is drawn upwardly, the shear ring 17 breaks to disengage the upper mandrel section 3 from the lower mandrel section 20. Thus, the upper mandrel section 3 may now be drawn upwardly through the casing 2 independently of the other components of the packing assembly, until the lower end of the upper mandrel section 3 engages the lower surface of the pin 18 which is fixedly positioned within the upper end of the lower mandrel section 20. The annular recess 16 may now be seen to be enlarged to the extent that the segmented nut assembly 14 has now become disengaged from the interior threads 15, and has thereupon fallen to the lower end of the annular recess 16. This releases the compressive load on the packing 21 and releases or removes opposition to downward travel of the lower expander 13 relative to the upper slips 12. In this respect, it should be noted that after the production stinger 35 has been removed from within the upper mandrel section 3 this also removes the backing which prevents inward contraction or collapse of the slotted portion 4 of the upper mandrel section 3. Accordingly, the upper expander 13 can now move away from the upper slips 12, thereby disengaging the upper slips 12 from the interior of the casing 2. Nevertheless, true disengagement of the slips 12 from the casing 2 occurs only when the splines 9 have moved to the upper end of the recess 10, whereupon the splines 9 engage the upper slip carrier 7 and carry it upwardly through the casing 2 with the upward moving upper mandrel section 3. As hereinbefore stated, the upper slip carrier 7 is linked to the upper slips 12 by means of a suitable T-connection 11. Furthermore, the upper slips 12 are linked at their lower end with the upper expander 13 by means of a suitable dovetail connection 28. Accordingly, upward movement of the upper slip carrier 7 will tend to carry the upper slips l2 and the upper expander 13 upwardly through the interior of the casing 2, as the upper mandrel section 3 is carried upwardly through the casing 2 by the retrieval tool 42.

When the upper mandrel section 3 engages the pin 18 linking it to the lower mandrel section 20, it will thereafter carry the lower mandrel section 20 with it up through the casing 2. If the packing 21 has not fully retracted, it will be forced to do so when the lower portion of the slot 24 engages the lower end of the key 23. Thereafter, further upward movement of the upper and lower mandrel sections 3 and 20 will carry the lower expander 25 out from under the lower slips 26, thereby disengaging the lower slips 26 from the interior of the casing 2. As hereinbefore explained, the lower slips and expander 25 and 26 are linked together by a suitable dovertail connection 27, and the lower slips 26 and the lower carrier 29 are suitably linked together by means of a T-connection 30 or other suitable means. Accordingly, further upward travel of the lower expander 25 will carry the lower slips 26 completely out of engagement with the interior of the casing 2, and upward through the casing 2. Upward movement of the slips 26 will, in turn, thereupon carry the lower slip carrier 29 up through the casing 2.

Referring now to FIG. 4, there may be seen a cross-sectional representation of a portion of the apparatus depicted in FIG. 1, wherein there may be seen the outer or exterior surface of the abutment portion 40 of the lower mandrel section 20 adjacent, but spaced from the inside surface of the casing 2. As further depicted, the segmented nut assembly 14 may be six separate nut segments equally spaced apart and about the exterior surface of the upper mandrel section 3, and disposed between the upper mandrel section 3 and the inside surface of the abutment portion 40 of the lower mandrel section 20. The tension member 33 of the setting tool may, of course, be centrally located in the upper mandrel section 3 as depicted in FIG. 1.

It will be apparent that an important feature of the present invention is a two-piece mandrel with a releasable support which opposes downward travel of the upper expander 13, and that separation of the two mandrel sections 3 and 20 disables this support to remove the opposition to downward travel of the upper expander 13 and to relieve compression in the packing 21.

The production stinger 35 depicted generally in FIG. 2 is generally conventional in function and purpose, except that the expansion shoulder 37 portion is provided for the purpose of supporting the slotted portion 4 of the upper mandrel section 3 against collapse when the upper slips 12 are wedged into engagement with the inside surface of the casing 2. Ac cordingly, a production stinger 35 may be used which has a special configuration for such purposes, or the shoulder 37 may be provided as an addition to a stinger 35 of more conventional design and function. The upper and lower slips l2 and 26 and expanders l3 and 25 may be of any conventional configuration, except as hereinbefore specifically noted.

It will be apparent from the foregoing that many other variations and modifications may be made in the structures and methods described herein without substantially departing from the essential concept of the present invention. Accordingly, it should be clearly understood that the forms of the invention described herein and depicted in the accompanying drawings, are exemplary only and are not intended as limitations in the scope of the present invention.

What is claimed is:

1. A well packer apparatus comprising an upper mandrel adapted to be passed longitudinally through a well casing or the like,

a lower mandrel adapted to be passed longitudinally through a well casing or the like and releasably secured to said upper mandrel,

a resilient packing body arranged about said lower mandrel and longitudinally compressible into fluidtight engagement with the inside surface of said casing,

lower expander means slidably mounted on said lower mandrel,

lower slip means slidably mounted on said lower mandrel for urging said lower expander means into compressive engagement with said packing body and adapted for upward wedged engagement between said casing and said lower expander means,

upper expander means slidably mounted on said upper mandrel,

upper slip means slidably mounted on said upper mandrel and cooperable with said upper expander means for anchoring against movement and for maintaining said fluidtight engagement of said packing body with said casing, and

locking means fixedly interconnecting one of said mandrels with said upper expander means for opposing upward movement of said one mandrel and disabled by movement of the other of said mandrels independent of said one mandrel.

2. The packing assembly described in claim 1, wherein said locking means is disabled by upward movement of said upper mandrel from and independent of said lower mandrel.

3. The packing assembly described in claim 2, wherein said locking means is slidably disposed relative to said upper mandrel and fixedly disposed between said lower mandrel and said upper expander means.

4. The packing assembly described in claim 3, wherein said locking means is disposed between the adjacent ends of said mandrels and between the exterior surface of said upper mandrel and the interior surface of said lower mandrel.

5. The packing assembly described in claim 4, wherein said locking means collapses relative to said interior surface of said lower mandrel upon upward movement of said upper mandrel from said lower mandrel and said locking means, and

wherein said collapse of said locking means enables disengagement of the anchoring of said upper slip means and said upper expander means.

6. The packing assembly described in claim 5, wherein said collapse of said locking means releases the fluidtight engagement of said packing body with said casing.

7. A well packer apparatus comprising upper mandrel means adapted to be passed longitudinally through a well casing or the like,

lower mandrel means also adapted to be passed longitudinally through said well casing and having its upper end provided with an external annular shoulder and adapted to encompass the lower adjacent end of said upper mandrel means,

a lower expander means slidably mounted on said lower mandrel means,

an annular resilient packing body disposed on said lower mandrel means between said shoulder and said lower expander means and compressible into fluidtight engagement with said casing,

a lower slip means slidably mounted on said lower mandrel means for driving said lower expander means into compressive engagement with said packing body and upwardly wedgeable between said casing and said lower expander means to oppose downward relaxation of said packing body locking means fixedly disposed between said adjacent ends of said mandrel means and releasable by upward movement of said upper mandrel means from and independent of said lower mandrel means, upper expander means slidably movable on said upper mandrel means and supported by said locking means, and

upper slip means slidably movable about said upper mandrel means and downwardly wedgeable between said casing and said upper expander means to oppose upward relaxation of said packing body.

8. The packer apparatus described in claim 7, wherein said locking means is slidably disposed about the encompassed lower end of said upper mandrel means and releasably fixed within said encompassing end of said lower mandrel means.

9. The packer apparatus described in claim 8, wherein said locking means is threadedly engaged with said encompassing upper end of said lower mandrel means and is further adapted to collapse and disengage from said threaded upper end thereof upon withdrawal of said lower end of said upper mandrel means from said encompassing upper end of said lower mandrel means.

10. The packer apparatus described in claim 9, wherein said locking means is a segmented nut assembly having external threads for engaging said upper end of said lower mandrel means and a relatively smooth internal surface for slidable engagement with said lower end of said upper mandrel means.

11. The packing assembly of claim 6 wherein said upper mandrel has means engageable with said upper slip means upon upward movement of said upper mandrel to permit retrieval of said upper slips and upper expander with said upper mandrel and wherein said lower mandrel has means engageable with said lower expander means upon upward movement of said lower mandrel to release said lower slip means from said wedged engagement with the casing and to permit retrieval of said lower expander and lower slips with said lower mandrel.

12. The packing assembly described in claim 11, further including pin means having one end fixedly connected to said upper end of said lower mandrel and having the other end inserted in a longitudinal slot in the lower end of said upper mandrel for limiting upward movement of said upper mandrel from said lower mandrel.

13. A well packer assembly for use in a well bore comprising:

telescopically arranged tubular members movable between longitudinally spaced positions,

means for releasably latching said members in one of said positions,

packing means disposed on one of said members,

first anchor means on said one member operable for gripping engagement with the wall of a well bore and for providing a support for said packing means,

' second anchor means on said other member operable for gripping engagement with the wall of a well bore and for providing a support for said packer assembly, said second anchor means when in engagement with the wall of a well bore preventing release of a compressed packing means, said second anchor means including slip means and expander means, means for normally interlocking said slip means to said other member, and cooperable means between said members for releasably supporting said expander means when said slip means are interlocked to said other member. 

1. A well packer apparatus comprising an upper mandrel adapted to be passed longitudinally through a well casing or the like, a lower mandrel adapted to be passed longitudinally through a well casing or the like and releasably secured to said upper mandrel, a resilient packing body arranged about said lower mandrel and longitudinally compressible into fluidtight engagement with the inside surface of said casing, lower expander means slidably mounted on said lower mandrel, lower slip means slidably mounted on said lower mandrel for urging said lower expander means into compressive engagement with said packing body and adapted for upward wedged engagement between said casing and said lower expander means, upper expander means slidably mounted on said upper mandrel, upper slip means slidably mounted on said upper mandrel and cooperable with said upper expander means for anchoring against movement and for maintaining said fluidtight engagement of said packing body with said casing, and locking means fixedly interconnecting one of said mandrels with said upper expander means for opposing upward movement of said one mandrel and disabled by movement of the other of said mandrels independent of said one mandrel.
 2. The packing assembly described in claim 1, wherein said locking means is disabled by upward movement of said upper mandrel from and independent of said lower mandrel.
 3. The packing assembly described in claim 2, wherein said locking means is slidably disposed relative to said upper mandrel and fixedly disposed between said lower mandrel and said upper expander means.
 4. The packing assembly described in claim 3, wherein said locking means is disposed between the adjacent ends of said mandrels and between the exterior surface of said upper mandrel and the interior surface of said lower mandrel.
 5. The packing assembly described in claim 4, wherein said locking means collapses relative to said interior surface of said lower mandrel upon upward movement of said upper mandrel from said lower mandrel and said locking means, and wherein said collapse of said locking means enables disengagement of the anchoring of said upper slip means and said upper expander means.
 6. The packing assembly described in claim 5, wherein said collapse of said locking means releases the fluidtight engagement of said packing body with said casing.
 7. A well packer apparatus comprising upper mandrel means adapted to be passed longitudinally through a well casing or the like, lower mandrel means also adapted to be passed longitudinally through said well casing and having its upper end provided with an external annular shoulder and adapted to encompass the lower adjacent end of said upper mandrel means, a lower expander means slidably mounted on said lower mandrel means, an annular resilient packing body disposed on said lower mandrel means between said shoulder and said lower expander means and compressible into fluidtight engagement with said casing, a lower slip means slidably mounted on said lower mandrel means for driving said lower expander means into compressive engagement with said packing body and upwardly wedgeable between said casing and said lower expander means to oppose downward relaxation of said packing body, locking means fixedly disposed between said adjacent ends of said mandrel means and releasable by upward movement of said upper mandrel means from and independent of said lower mandrel means, upper expander means slidably movable on said upper mandrel means and supported by said locking means, and upper slip means slidably movable about said upper mandrel means and downwardly wedgeable between said casing and said upper expander means to oppose upward relaxation of said packing body.
 8. The packer apparatus described in claim 7, wherein said locking means is slidably disposed about the encompassed lower end of said upper mandrel means and releasably fixed within said encompassing end of said lower mandrel means.
 9. The packer apparatus described in claim 8, wherein said locking means is threadedly engaged with said encompassing upper end of said lower mandrel means and is further adapted to collapse and disengage from said threaded upper end thereof upon withdrawal of said lower end of said upper mandrel means from said encompassing upper end of said lower mandrel means.
 10. The packer apparatus described in claim 9, wherein said locking means is a segmented nut assembly having external threads for engaging said upper end of said lower mandrel means and a relatively smooth internal surface for slidable engagement with said lower end of said upper mandrel means.
 11. The packing assembly of claim 6 wherein said upper mandrel has means engageable with said upper slip means upon upward movement of said upper mandrel to permit retrieval of said upper slips and upper expander with said upper mandrel and wherein said lower mandrel has means engageable with said lower expander means upon upward movement of said lower mandrel to release said lower slip means from said wedged engagement with the casing and to permit retrieval of said lower expander and lower slips with said lower mandrel.
 12. The packing assembly described in claim 11, further including pin means having one end fixedly connected to said upper end of said lower mandrel and having the other end inserted in a longitudinal slot in the lower end of said upper mandrel for limiting upward movement of said upper mandrel from said lower mandrel.
 13. A well packer assembly for use in a well bore comprising: telescopically arranged tubular members movable between longitudinally spaced positions, means for releasably latching said members in one of said positions, packing means disposed on one of said members, first anchor means on said one member operable for gripping engagement with the wall of a well bore and for providing a support for said packing means, second anchor means on said other member operable for gripping engagement with the wall of a well bore and for providing a support for said packer assembly, said second anchor means when in engagement with the wall of a well bore preventing release of a compressed packing means, said second anchor means including slip means and expander means, means for normally interlocking said slip means to said other member, and cooperable means between said members for releasably supporting said expander means when said slip means are interlocked to said other member. 